The long-term goal of the proposed research is to use nervous tissue in culture in the study of the mechanisms by which the central nervous system responds to the drugs which induce dependence. The first cultures to be established will be long-term organized cultures from areas of the hypothalamus, striatum, and substantia nigra. These tissue preparations have the advantages of being functionally discrete neuronal populations which can be used at various times when synaptic contacts are absent, developing, or fully mature. The interactions of narcotic analgesic drugs (and later, of other types of dependence- producing drugs) with components of the neural cell membrane will be examined chemically and microscopically by the use of light and electron microscopy. The effects of narcotic analgesics and antagonists on the uptake, release and post-synaptic reactions of the neurotransmitters will be measured both by subcellular fractionations using labeled biogenic amines and by microfluorescence. Since synaptic function can be measured bioelectrically in these preparations, the effects of opiates on neural transmission will be assessed directly, as will general effects on tissue differentiation. New thoughts concerning the concept of synaptic plasticity suggest that it is possible not only to develop new synapses but to develop wrong synapses as well. These studies will examine the effect of opiates on synaptic development.